Added style definitions in loadui-style.css to show an arrow in expander-button in the toolbox-skin
Merge branch 'sprint9' of https://github.com/SmartBear/loadui into sprint9
Added styling to the toolboxes category-button, and made it look as close to the old loadui as possible
hidden buttons are now totally hidden instead of disabled, also fixed arrow color of hovered buttons into #222222
Merge branch 'sprint9' of https://github.com/SmartBear/loadui into sprint9